3D-printed ultrasound cast could save us costly surgeries

Last year the National Institute for Health and Care
Excellence (NICE)approved a low-intensity
ultrasound system, known as Exogen, for use in the NHS on
bone fractures that fail to heal after nine months. Now, Turkish
industrial designer Deniz
Karasahin wants to make that healing a more beautiful, and
patient-friendly experience.

"The process started itself, somehow," Karasahin told
Wired.co.uk of his Osteoid cast development. "I was asked to make a
small informative presentation about 3D technologies at the Izmir
Chamber of Commerce. At the time I was also following the growth of
the industry very closely and wanted to contribute. The cast idea
was the most promising area because it added the most benefit
compared with contemporary applications."

3D printing hearts and livers might be in the early development stages, but 3D
printing medical devices and parts has been ongoing for years -- in
2013, iLab Haiti began using MakerBot printers to create umbilical
cord clamps on the spot. And if anything is ripe for disruption,
it's the sweaty, stinky, itchy plaster cast that has remained
relatively unchanged for decades.

3D printing the cast itself is nothing new -- there are plenty
of designers experimenting with different geometric patterns and
last year we featured Jake Evill's beautifully designed Cortex cast that behaves like
a brace and is tailored to the individual from a 3D scan. It's
washable, breathable, discreet and can be made denser in the areas
round the fracture that need more support.

Karasahin's version looks very similar -- albeit with a
different geometric pattern -- clinging close to the subject's skin
and wrapping round their thumb. But there are a few key
differences. "We share a more contemporary style but this style is
also mainstream in the design world," notes Karasahin. "His
form/pattern inspiration is geometric-based and also the
geometric/algorithmic logic is related to the place of the injury.
In my case the form/pattern inspiration is different -- I was
inspired by the pattern of spongy bone geometry because of its
semiotic relation with a medical cast, and the logic behind my
algorithm aims for an equally distributed stronger structural
integrity of the cast."

Rather than snapping closed the Osteoid, made up of two pieces,
also features a secondary, secure locking mechanism to ensure it
doesn't open when in use. Of course the most obvious difference, is
the proposal for an ultrasound port, where devices similar to
Exogen's can be introduced.

"I read the clinical studies about this tech, and some of them
were almost 20 years old," says Karasahin. "After talking with an
orthopaedist MD I learnt about the current application problems
which prevent this tech from being widely used."

The most obvious of these, is how you reach the skin to place
the ultrasound probes if it's wrapped up in a cast. Typically a
hole is cut in the cast to allow a transducer to touch the skin
where the fracture is. Karasahin explains that the site of the skin
will also swell, causing the patient discomfort. With all the holes
in the Osteoid, there's no chance of that.

Clinical studies have shown that the ultrasound waves promote
bone healing by stimulating the production of growth factors and
proteins that increase removal of old bone, and increase the
production of new bone.

The designer has already been contacted by private and
government-owned clinics in the US, looking to launch trials (the
Osteoid is still at the concept stages right now).

"It is the medical industry that is the most excited -- it is
all positive," said Karasahin. "I also have received so many emails
from people who are willing to put one on instantly."

The design has great promise, but there's a few things to
remember. The Osteoid is being touted with a promise that, once
hooked up to ultrasound for 20 minutes a day, it will help reduce
the time it takes for the injury to heal by 38 percent. The heal
rate for non-union fractures that are totally cut in two increases
by 80 percent. Those figures are based on clinical trials
already carried out separately.

Exogen, the ultrasound device given the okay by the NHS last
year following an investigation by NICE, recommends patients
receive 20-minute daily sessions they can administer themselves at
home each day, speeding up healing by about 38 percent. The Osteoid
is simply putting together two already well-established concepts --
the 3D printed cast and ultrasound bone healing therapy.

The Exogen system is for non-union fractures, but the lengthy
NICE report is very clear in its findings -- it does not believe
the device is suitable for any fractures that have failed to heal
before nine months. This may be largely down to cost-efficiency.
The only reason it is cost saving, is it can help prevent
last-resort surgeries.

The NICE report concludes that the system, when applied to long
bone fractures with non-union that have failed to heal after nine
months, "shows high rates of fracture healing". It estimates this
could deliver cost savings of "£1,164 per patient compared with
current management, through avoiding surgery".

However, of use prior to that nine month stage, it stipulates
that although there is some evidence of healing when used before
the nine months: "There are substantial uncertainties about the
rate at which bone healing progresses without adjunctive treatment
between three and nine months after fracture, and about whether or
not surgery would be necessary. These uncertainties result in a
range of cost consequences, some cost-saving and others that are
more costly than current management."

So it could be that using the device before nine months would be
suitable one day -- there simply isn't enough evidence to back up
the measures as being worth the investment. Throw in the cost of a
3D printer and a 3D scanner, along with software and development
time, and the NHS will probably tell you where to go. But as the
costs of the printers themselves continue to plummet, and this is
weighed up alongside the ease with which superior therapies can be
delivered to a patient that is far happier with their breathable,
comfortable Osteoid, we might see an updated NICE report in the
future.